This invention relates generally to wire connectors, and more specifically, to a twist-on wire connector having a lubricant thereon to reduce the torque required to set the electrical wires in the wire connector and at the same ensure that the electrical wires are securely engaged so that normal thermal expansion and contraction or shock and vibration conditions will not cause the wires to loosen in the connector.
The concept of wire connectors for connecting the junction of two or more wires together by twisting a cap on the wires is old in the art. Wire connectors are well known in the art and generally comprise an outer housing with a tapered threaded interior to permit a user to insert wires into the tapered opening. To use a wire connector, the user inserts the twisted ends of electrical wires into a cavity on the inside of the wire connector. The user then holds the wire in one hand and with the other hand twists the wire connector. The twisting action pulls the junction ends of the wires into a low resistance electrical contact.
If the connector is located in a wet location it is necessary to place a waterproof sealant around the connector. In order to prevent water or moisture from entering the connector and forming an oxidation layer over the ends of the wire the user inserts the wire connector and the wire into some type of a waterproof potting compound. The compound may be either a non hardening or a hardening compound. In either case the compound creates a waterproof capsule over the wire connector and the junction ends of the electrical wires.
The prior art process is time consuming because it involves two separate steps as well as the nuisance of having separate potting compounds and containers to hold the potting compound. A second generation improved twist-on wire connector wherein the wires can be encapsulated and sealed in a twist on wire connector to prevent water or moisture from entering the connector is shown in my U.S. Pat. Nos. 5,113,037; 5,023,402 and 5,151,239. The second generation twist-on wire connectors permits the user in one continuous action to simultaneously form the junction ends of wire leads into a low resistance electrical connection that is surrounded by a waterproof sealant to form a waterproof covering around the junction ends of the wire leads.
Under certain dynamic conditions, such as vibration and shock, or large temperature changes the wires in the twist-on wire connector can become loosened and thus lower the integrity of the connection between the wires in the twist on wire connectors by either increasing the electrical resistance or decreasing the contact area or both. I call the present invention a third generation electrical twist-on wire connector wherein the integrity of the low resistance electrical connection of the twist-on wire connector is actually enhanced by placing a small amount of self-adhering lubricant in the twist-on wire connector. Generally, to enhance the electrical conductive between connector and wire one needs only a small amount of self-adhering lubricant to provide an enhanced low resistance electrical connection. In the present invention, it has been found that when a small amount of a self-adhering lubricant has been incorporated into the wire connector it results in an enhanced low resistance electrical connection.
In order to ensure that twist-on wire connectors remain in a low-resistance electrical connection when subject to environmental conditions of shock and vibration one prior art method is to encapsulate the twist-on wire connectors in a solid resin. In other methods tools may be used to apply extra torque to the wires to cause further engagement of the threads of the wire connector with the electrical wires. In the present method one need not resort to encapsulation with a solidified resin and one need not resort to using tools to enhance the torque since it has been found that even though a lubricant is used the suspected detrimental effects of use of a lubricant film between the wire and the wire connector is overcome by the greater physical engagement between the wires which can be obtained by use of the lubricant. That is, the lubricant allows one to reduce the torque that may be required to make a secure connection in a twist-on wire connector. As a result one can hand tighten a twist-on wire connector containing a small amount of self-adhering lubricant and provide for greater electrical contact between the wires which results in retention of the low-resistance electrical connection even in the presence of forces such as vibration and shock.
Briefly, the present invention is an improved twist-on wire connector that permits the user to form the junction ends of wire leads into a low resistance electrical connection with the twist-on wire connector including a self adhering lubricant located along a portion of the interior of the twist-on wire connector. The wires are drawn into the housing by a spiral thread through the twisting action of the wires with respect to housing. As the wires are drawn into the spiral thread, the frictianl resistance to the rotation of the wires increases until the wires can no longer be hand twisted into the wire connector. Once the wires are drawn into contact with the lubricant the torque resistance, which is a result of frictional resistance between the wires and the spiral thread, decreases while the radial compressive forces between the wires and the spiral thread are substantially unaffected. Consequently, the rate of torsonial resistance decreases allowing the wires to be brought into further electrical contact along a greater length through only hand tightening while at the same time the radially compressive forces on the wires are greater thus ensuring a low resistance electrical contact that remains stable over an extending period of time. Because only a small amount of self-adhering lubricant is needed within the wire connector to provide an enhanced low-resistance electrical connection problems of the self-adhering lubricant accidentally coming into contact with the exterior housing of other twist-on wire connectors is minimized even if caps are not used on the twist-on wire connectors.